Skilled Nursing Services while on hospice

I have a patient who resides in a nursing home (SNF).  On hospice with Cancer of Colon.  He fell and fractured his hip.  He underwent an ORIF.  While hospitalized remained on service (routine level of care) because the fall and fracture were unrelated to his hospice diagnosis.  Has now returned to nursing home.  The nursing home informed us (the hospice) that the patient would be getting Part "A" PT and OT.  I informed them that billing for skilled rehab under Part "A" is not permitted.  They would have to bill Part "B".  The facility told me that this is a rare special circumstance which allows both hospice and a nursing home to bill part "A".  

My question is "Who is right?"  If the nursing home is correct can you tell me where to find this specific information.

Thanks